The proposal, likely to come up for a vote next week, would allow an appointee to an open Senate seat to hold that seat for two full years if the vacancy occurs within 150 days of a regularly scheduled primary election.

Current law would give voters the right to pick a candidate to fill the remainder of a Senate term in the subsequent general election if a vacancy occurs by May 31, six weeks away. If the vacancy occurs after that date, anyone appointed by Gov. Doug Ducey (R) would hold the seat until the 2020 election.

If the change is made, and if Republicans are able to gather enough votes to invoke an emergency clause that implements the law immediately, any appointment made after March 31 — 2 1/2 weeks ago — would hold the seat until 2020.

Democrats say the proposed measure is meant to allow Republicans to avoid putting McCain’s seat at risk in a year when the political wind is at Democrats’ backs.

“It’s hard to get away from the fact that Republicans are thinking more about their chances of keeping the second Senate seat than they are about the well-being of Sen. McCain,” said state Sen. Steve Farley (D). “To be doing this kind of politically driven action at this moment just seems — it’s just so bad.”

“I think everybody was just trying to make this process fair. I think it’s unfortunately probably much ado about little,” Yarbrough said. “It’s not like this is going to create some advantage.”

Democrats have pledged to vote in lockstep against the measure, denying it the two-thirds margin necessary to invoke an emergency clause. That means the May 31 deadline is likely to remain in place.

Republicans pulled the bill from consideration on Wednesday, when it appeared they did not have the votes to pass the emergency clause. The bill is more likely to hit the floor next week, when the legislature returns to session.

Farley, who is running for governor, said the last-minute proposal was part of a larger effort by Arizona Republicans to change the way elections are conducted. In recent years, the GOP has sought to limit voter-sponsored ballot initiatives and to change absentee ballot collection rules.

“I keep seeing members of the Republican majority taking away people’s voting rights in every different way,” he said in an interview. “It’s been an ongoing series of efforts to try to disenfranchise the voters of Arizona, and it’s got to stop.”

If a second Senate seat were on the ballot, Republicans could face the daunting prospect of defending both seats in an unfavorable political climate.

The legislation itself, and the GOP’s interest in the emergency clause that would allow it to take effect immediately, have raised new questions about McCain’s health. McCain remains hospitalized at the Mayo Clinic, about 20 miles from the state capitol, after undergoing surgery for an intestinal ailment related to his cancer treatment.

Since McCain announced his diagnosis last year, Arizona politicians have been engaged in a quiet and at times unseemly campaign for his seat, on the assumption it would be open before McCain’s term expires in 2022. Ducey, who has the sole power to appoint anyone to a vacant Senate seat, has grown angry at some contenders who are openly jockeying for the appointment.

“I have found it a little bit off color, some of the prognosticators and pundits who have been making these predictions as to the senator’s outcome,” Ducey said on KTAR radio in December. “To the politicians out there that have been openly lobbying for this position, they’ve basically disqualified themselves by showing their true character.”

“I think everybody kind of got the message. I think the governor made it clear at one point that [lobbying for the appointment] wasn’t going to help anybody,” Yarbrough said of Ducey’s brush-back pitch.